In real life you can't just look at a map and fire a gun at the same time. You have to put your gun down and look at the map, then put the map down and pick up your gun.

I was just playing GTA5 with the map disabled and it REALLY forces you to be more aware of your surroundings and to be more careful. You can look at the map by pressing pause.

Also you have to "search" for enemies instead of just looking where enemies are on the radar.